Rotary piston device

ABSTRACT

AN IMPROVEMENT IN A ROTARY PISTON DEVICE COMPRISING A SHAFT, A HOUSING ROTATABLY MOUNTED WITH RESPECT TO THE SHAFT, A BANK OF CYLINDERS RADIALLY ARRANGED AROUND THE HOUSING, PISTONS SLIDABLY MOUNTED WITHIN THE CYLINDERS AND LINK RODS CONNECTED TO THE PISTONS, WHICH IMPROVEMENT CONSISTS OF (A) AN INTERNAL THROW PORTION OF THE SHAFT HAVING AN AXIS DISPLACED FROM THE AXIS OF THE END THROW PORTIONS OF THE SHAFT, (B) THE AXIS OF THE HOUSING COINCIDING WITH THE AXIS OF THE END THROW PORTIONS OF THE SHAFT, (C) A CENTER WHEEL ROTATABLY MOUNTED AROUND THE INTERNAL THROW PORTION OF THE SHAFT, TO WHICH THE LINK RODS ARE ATTACHED, (D) A CENTER WHEEL INTERNAL GEAR AFFIXED TO THE CENTER WHEEL, THROUGH WHICH THE SHAFT PASSES, (E) A HOUSING INTERNAL GEAR AFFIXED TO THE HOUSING, THROUGH WHICH THE SHAFT PASSES, (F) SAID HOUSING INTERNAL GEAR AND SAID CENTER WHEEL INTERNAL GEAR HAVING A 1:1 GEAR RATIO, AND (G) A TRANSFER EXTERNAL GEAR THROUGH WHICH THE SHAFT PASSES, THE GEAR TEETH OF WHICH MESH WITH THE GEAR TEETH OF BOTH THE CENTER WHEEL INTERNAL GEAR AND THE HOUSING INTERNAL GEAR SO THAT THE CENTER WHEEL INTERNAL GEAR, THE HOUSING INTERNAL GEAR AND THE TRANSFER EXTERNAL GEAR ALL ROTATE IN THE SAME DIRECTION. THE IMPROVED DESIGN AVOIDS COUNTERBALANCING PROBLEMS SUCH AS ARE ENCOUNTERED IN DESIGNS UTILIZING MASTER RODS OR SEGMENTATION OF THE CRANK THROW BEARINGS. THE IMPROVED ROTARY PISTON DEVICE MAY BE USED IN APPLICATIONS FOR WHICH CONVENTIONAL PISTON-CYLINDER UNITS OR DIAPHRAGMS ARE EMPLOYED, SUCH AS AIR PRESSURE PUMPS, VACUUM PUMPS, HYDRAULIC PUMPS, AND STEAM, GASOLINE OR DIESEL ENGINES OF TWO OR FOUR CYCLE DESIGN.

q 1971 R. c. SHOEMAKER 3,605,564

nouny rrswon DEVICE Filed Dec. 22, 1969 2 Sheets-Sheet 1 FIG. 1 i

INVENTOR ROGER C. SHOEMAKER ATTORNEY Sept. 20, 1971 R. C. SHOEMAKER noun: rrs'ron DEVICE Filed Dec. 22. 1969 2 uumrnnr 2| 2" 25 i 19 M W l l 2 Sheets-Sheet. 2

INVENTOR. ROGER C. SHOEMAKER BYW/ ATTORNEY.

United States Patent U.S. Cl. 91-495 4 Claims ABSTRACT OF THE DISCLOSURE An improvement in a rotary piston device comprising a shaft, a housing rotatably mounted with respect to the shaft, a bank of cylinders radially arranged around the housing, pistons slidably mounted within the cylinders and link rods connected to the pistons, which improvement consists of (a) an internal throw portion of the shaft having an axis displaced from the axis of the end throw portions of the shaft; (b) the axis of the housing coinciding with the axis of the end throw portions of the shaft; a center wheel rotatably mounted around the internal throw portion of the shaft, to which the link rods are attached; ((1) a center wheel internal gear afiixed to the center wheel, through which the shaft passes; (e)

a housing internal gear afiixed to the housing, through which the shaft passes; (f) said housing internal gear and said center wheel internal gear having a 1:1 gear ratio; and (g) a transfer external gear through which the shaft passes, the gear teeth of which mesh with the gear teeth of both the center wheel internal gear and the housing internal gear so that the center wheel internal gear, the housing internal gear and the transfer external gear all rotate in the same direction. The improved design avoids counterbalancing problems such as are encountered in designs utilizing master rods or segmentation of the crank throw bearings. The improved rotary piston device may be used in applications for which conventional piston-cylinder units or diaphragrns are employed, such as air pressure pumps, vacuum pumps, hydraulic pumps, and steam, gasoline or diesel engines of two or four cycle design.

BACKGROUND OF THE INVENTION Rotary piston devices in which pistons are given rectilinear motion relative to cylinders by holding a crankshaft in a fixed position and revolving the cylinders about the crankshaft, are known in the art. These devices have been variously referred to in the art as bi-rotary engines, rotary piston engines and simply rotary engines. I prefer to call the basic mechanical device a rotary piston device. Rotary piston devices have a wide variety of applications and may be used generally in applications for which conventional piston-cylinder type units or diaphragm units are employed.

Rotary piston devices have a number of significant advantages over conventional type piston-cylinder devices. Such advantages include greater efiiciency due to reduction of resistance to changes in inertia, better intake and exhaust separation due to action of centrifugal force on gases in the cylinders, greater economy of manufacture due to the possibility of greater standardization of parts, inherent air cooling by the action of the revolving cylinders which form the flywheel, lighter weight and greater compactness.

Unfortuantely, rotary piston devices have not come into widespread usage due to certain disadvantages of previously known designs. Many previously known designs, as evidenced by U.S. Pats. 2,234,187, 2,242,231 and 2,203,692, for example, incorporate a master rod type connection between the rotating piston units through the link rods and the shaft. This arrangement has proven unsatisfactory due to the fact that under conditions of rotation, each link pin in the master rod assembly spins in a different orbit. A difiicult arrangement of counterbalances and weights is required to balance the system and the additional parasite weight causes diflicult inertia problems and reduces efiiciency. Moreover, the cylinders in such devices will have different stroke characteristics and asymmetrical firing orders. Previously known designs also have included the segmentation of the shaft bearings and severing of the link rods so that they connect different segments of the hearings. Such devices have not proved satisfactory as they are fraught with many mechanical difiiculties.

It is accordingly a major object of this invention to provide an improved rotary piston device.

It is another object of this invention to provide a rotary piston device which does not suffer from the disadvantages of master rod type connections between the rotating pistons and the shaft, or from the disadvantages caused by segmentation of the shaft bearings.

Other objects and advantages of the invention will become apparent from the following description.

SUMMARY OF THE INVENTION I have found that the above objects are accomplished in'a rotary piston device comprising a shaft, a housing rotatably mounted with respect to the shaft, a bank of cylinders radially arranged around the housing, pistons slidably mounted within the cylinders and link rods connected to the pistons by providing (a) an internal throw portion of the shaft having an axis displaced from the axis of the end throw portions of the shaft; (b) the axis of the housing coinciding with the axis of the end throw portions of the shaft; (0) a center wheel rotatably mounted around the internal throw portion of the shaft, to which the link rods are attached; (d) a center wheel internal gear aflixed to the center wheel, through which the shaft passes; (e) a housing internal gear affixed to the housing, through which the shaft passes; (f) said housing internal gear and said center wheel internal gear having a 1:1 gear ratio; and (g) a transfer external gear through which the shaft passes, the gear teeth of which mesh with the gear teeth of both the center wheel internal gear and the housing internal gear so that the center wheel internal gear, the housing internal gear and the transfer external gear all rotate in the same direction.

As will readily be appreciated by those skilled in the art, the subject rotary piston device may be employed in applications for which rotary piston devices have previously been adapted. In view of the increased feasibility afforded by the new design, the subject rotary piston devices may be used generally in any application for which conventional piston-cylinder type units or diaphragm units can be employed, such as air pressure pumps, vacuum pumps, hydraulic pumps, and steam, gasoline or diesel engines of two or four cycle design.

The modes and details of incorporating the subject improved rotary piston devices into useful machines in which they have been used before, or in machines, which may be devised, do not form a part of this invention and accordingly need not be described herein. The details of construction of rotary piston devices, including cylinder construction, lubrication, provision for ignition, sealing and power take-off, are well known or would be obvious to those skilled in the art. Likewise, details relating to incorporation of the subject turbine devices in engines, pumps and other applications are well known or are obvious to those skilled in the art. Illustrative specific applications for the same are disclosed in the following patents: U.S. Pats. 2,203,692; 2,207,749; 2,234,187; 2,242,231 and 3,279,445. Many other applications and designs are known and may be devised by those skilled in the art and persons skilled in the art need not be told details of construction or how to use the subject devices.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a transverse sectional view of the improved rotary piston device of the invention taken substantially along line 11 of FIG. 2.

FIG. 2 is a longitudinal sectional view of the improved rotary piston device of the invention, taken substantially along line 2-2 of FIG. 1.

FIG. 3 is a longitudinal sectional view of an embodiment of the invention showing two rotary piston devices like the one shown in FIG. 2, mounted in series.

FIG. 4 is a longitudinal sectional view of another embodiment of the invention showing a rotary piston device like the one shown in FIG. 2, but in which the arrangement in combination of the center wheel internal gear, housing internal gear and transfer external gear is duplicated on each side of the center wheel.

DETAILED DESCRIPTION OF THE INVENTION AND OF THE PREFERRED EMBODIMENT Referring to the drawings, the improved rotary piston device, in accordance with the invention, comprises the usual shaft on which a rotatable housing 11 is mounted around bearing surfaces 23 and 24. A plurality of cylinders 12 are symmetrically, radially arranged around housing 11 in a plane perpendicular to shaft 10. Pistons 13 are slidably mounted in each of the cylinders. Link rods 14 are connected to each piston by means of link pins 15. In accordance with the improvement of the invention, the end of each link rod opposite the piston is connected to a center wheel 16 by means of link rod pins 17. Center Wheel 16 preferably contains a circumferential recess 18 as shown in FIG. 2. to facilitate mounting of link rods 14. The center wheel is rotatably mounted on an internal throw portion 19 of shaft 10. It can be seen therefore that the axis of the center wheel is displaced from the axis of the end throw portions of the shaft. Rotation of the cylinders and housing about the shaft will result in the imparting of rectilinear motion of the pistons relative to the cylinders. A center wheel internal gear 20 is immovably mounted to or constructed integrally with center wheel 16. This gear may have the same or different diameter than the center wheel. The internal gear meshes with a transfer external gear 21 along a portion of its surface. Another portion of the surface of transfer external gear 21 in turn meshes with a housing internal gear 22. The housing internal gear 22 may be the same or different diameter as center wheel internal gear 20, but housing internal gear 22 and center wheel internal gear 20 have a 1:1 gear ratio. When the housing internal gear is a difierent diameter than the center wheel internal gear, the transfer external gear is stepped to maintain the desired 1:1 gear ratio between the housing internal gear and the center wheel internal gear. Housing internal gear 22 is immovably mounted to or made integral with the housing. In operation, the cylinders rotate, along with housing 11 and housing internal gear 22. This causes transfer external gear 21 to rotate in the same direction. Transfer external gear 21 engages center wheel internal gear 20. The rotation of transfer external gear 21 thus causes center wheel internal gear 20 to rotate in the same direction and at the same speed as housing internal gear 22, center wheel 16 and cylinders 12. The net result is the synchronized rotation of the cylinders, pistons, center wheel and housing about the shaft.

FIG. 3 shows two rotary piston devices, as illustrated in FIG. 2, mounted in series, with one of the rotary piston devices inverted with respect to the other. To facilitate illustration, the parts in FIG. 3 which correspond to the parts in FIG. 2 are shown with the same numbering. The new parts of the second (right-hand) rotary piston device are given numbers which correspond to the equivalent parts in the first (left-hand) rotary piston device, except that the numbers for the second device are followed by the prime symbol (as in 14).

FIG. 4 shows a rotary piston device with duplication of the gear train on each side of the center wheel. To facilitate illustration, the parts in FIG. 4 which correspond to the parts in FIG. 2 are shown with the same numbering. The new parts in the duplicate side (righthand) of the gear train are given numbers which correspond to the equivalent parts in the original side (lefthand) of the gear train, except that the numbers for the duplicate side are followed by the double prime symbol (as in 20" The following is an illustrative application of a novel rotary piston device in accordance with the invention. The illustration is that of a two stage air compressor. Two radial banks of cylinders as described herein are mounted, as described further herein, on a common shaft which is maintained stationary. The shaft has two end throw portions, a first internal throw portion having an axis displaced above the axis of the end throw portions and a second internal throw portion having an axis displaced below the axis of the end throw portion. The two banks of cylinders function as the two stages of the compressor. The low pressure stage has a larger displacement than the high pressure stage. This relationship is built in by reducing the bore, stroke, or number of cylinders in the high pressure stage. The precise displacement ratios between stages to be used may vary with particular needs and may readily be determined by one of ordinary skill in the art. A housing completely encloses the cylinder banks and is rotatably mounted with respect to the shaft as further described herein. Two center wheels are rotatably mounted, respectively, around the two internal throw portions of the shaft. With this arrangement when the piston on the low pressure side is at the top of its stroke, the opposing piston on the high pressure side is at the bottom of its stroke, and vice-verse. Two opposing sets of center wheel internal gears afiixed to the center wheels, housing internal gears aflixed to the housing, and transfer external gears as described herein are provided. An extra set of the center wheel internal gear, the housing internal gear and transfer external gear may be provided on the opposite side of one or both of the center wheels for extra strength if desired. The housing is caused to rotate by a V-belt using an electric motor as the prime mover. Screens mounted on each cylinder intake for the low pressure stage are provided for filtering intake air. Air is fed to the high pressure stage cylinder from the low pressure stage cylinders. Air discharged from the high pressure stage is transported away from the unit by means of a rotary seal mounted on the stationary shaft. Cooling of the cylinders is accomplished by means of the air flow created by the rotating cylinders. Air vanes are positioned to direct the cooling air through the cylinders. Lubrication of the unit may be provided with conventional lubricating lines and seals.

It is to be understood that the invention is not to be limited to the structures and embodiments particularly described herein. Anyone of ordinary skill in the art can readily devise variations and modifications of such structures and embodiments, as well as applications therefore, without departing from the scope and spirit of the invention. For example, the number of cylinders in the devLce may be varied. A duplicate gear train can be mounted on the opposite side of the center wheel to provide increased strength. The shaft can have multiple internal throw portions with center wheels and accompanying gear trains associated with each internal throw portion. The shaft could be hollowed to provide access to the interior of the device for lubrication or induction. A plurality of rotary piston devices as described herein can be mounted together in series. Means for liquid cooling of the rotary piston devices can readily be devised. The novel rotary piston devices may be incorporated into mechanical applications in which the cylinder bank and housing rotate,

with the shaft remaining stationary or in which the shaft rotates, with the cylinder bank and the housing remaining stationary. In those embodiments in which the shaft rotates, counter weights would be required as with master rod type assemblies. However, such embodiments would still offer substantial advantages over those incorporating master rod assemblies in that with assemblies employing the novel devices, all the cylinders will have identical stroke characteristics and symmetrical firing orders. More over, the link rod angles would be relatively small since the link rods oscillate only slightly from the parallel to the axis of the cylinders throughout the cycle.

The invention is to be limited only by a reasonable interpretation of the appended claims.

I claim:

1. In a rotary piston device comprising a shaft, a housing rotatably mounted with respect to the shaft, a bank of cylinders radially arranged around the housing, pistons slidably mounted within the cylinders and link rods connected to the pistons, the improvement which consists of, in combination:

(a) an internal throw portion of the shaft having an axis displaced from the axis of the end throw portions of the shaft;

(b) the axis of the housing coinciding with the axis of the end throw portions of the shaft;

(c) a center wheel rotatably mounted around the internal throw portion of the shaft, to which the link rods are attched; and a 4 (d) gear train for synchronizing the rotation of the cylinders, pistons, center wheel and housing with respect to the shaft consisting of (i) a center wheel internal gear afiixed to the center wheel, through which the shaft passes; (ii) a housing internal gear afllxed to the housing through which the shaft passes, said housing internal gear and said center wheel internal gear having a 1:1 gear ratio; and

(iii) a transfer external gear through which the shaft passes, the gear teeth of which mesh with the gear teeth of both the center wheel internal gear and the housing internal gear, so that the center wheel internal gear, the housing internal gear and the transfer external gear all rotate in the same direction.

2. A rotary piston device according to claim 1 comprising a plurality of rotary piston devices as defined, mounted together in series.

3. A rotary piston device according to claim 1 in which the arrangement in combination of the center wheel internal gear, housing internal gear and transfer external gear is duplicated on each side of the center wheel.

4. A rotary piston device according to claim 1 in which the housing internal gear has the same diameter as the center wheel internal gear.

References Cited UNITED STATES PATENTS 685,141 10/1901 Hirth 123-44 1,377,723 5/1921 Mufliy 12344 2,256,094 9/1941 Lynch 123-55A 2,683,422 7/1954 Richards, Jr. 12344 ALLAN D. HERRMANN, Primary Examiner US. Cl. X.R. 123-44R 

